1. Field of the Invention
The present invention generally relates to a touch input system. More particularly, the present invention relates to an input device suitable for emitting light and a touch screen using the input device.
2. Description of Related Art
Display panels traditionally serve the role of displaying the information or the output from a system, while other input device or devices provide inputs to the system. Interactive devices, such as a touch panel that can receive a user's input via touching the display panel, combines both output and input functions and allow a user to interact with the display or the system coupled to the display. As an example, devices such as personal digital assistants (PDAs), mobile phones, personal computers (PCs), tablet PCs, etc. have incorporated touch panels for providing users with more input choices.
Conventional touch panels or touch screens have a number of different designs, such as resistive type, surface-wave type, capacitive type, and infrared-ray type designs. All of these designs typically require combining a display device with a separate touch panel sheet. No matter what type of touch panel, it tries to provide a more convenient way for users, for example, the resistive type, surface-wave type, capacitive type, and infrared-ray type touch panel are operated by users' fingers or stylus. The in-cell type optical touch display panels could be operated by light or shadow, and the touch position is located by photo sensors designed in the in-cell type display panel. Therefore, touch display panel includes a display panel suitable for sensing a light signal emitted or blocked by a stylus to be operated. When a optical pen used as a positional indicator of the in-cell type optical touch display panel, the display panel is capable of displaying a line according to the light signal emitted by the stylus. Several arrangements have been proposed for an optical pen which has a pressure sensitive mechanism, and allowed to produce a certain change when the pen pressure was applied thereto.